Supportive apparel is needed and used by many people. For example, many people employ orthopedic or therapeutic braces to reduce loading to a particular portion of the body. Supportive apparel also includes footwear.
Orthopedic/Therapeutic Braces
There are many people who have clinical need to reduce the force borne by a particular surface—such as the surface of an arthritic joint, or the plantar foot surface when there is a foot ulcer.
Many people experience joint pain. In fact, it is estimated that well over 20 million Americans suffer from the effects of osteoarthritis—a condition in which there is breakdown or erosion of the cartilage that lubricates the bearing surfaces of the bones in a joint. This results in pain and stiffness.
Cartilage protects bone surfaces at joints and produces fluid to lubricate the joint. When too much cartilage in a joint is worn away, compression in the joint can push two unlubricated bone surfaces together. When the joint is flexed and the unlubricated surfaces are moved against each other, the pain can be severe.
The pain of osteoarthritis is exacerbated when the unprotected bone surfaces are pushed against each other—as for example pain from an arthritic knee during walking. Without load bearing, the osteoarthritis patient may well have full range of motion in the joint, but the pain of bearing weight pushes bone against bone (without the protective effect of cartilage and synovial fluid) and thus makes even walking unbearably painful. If the bone surfaces could be kept apart even a minute distance, then the pain would subside.
Treatments utilized by these patients include anti-inflammatory medication, analgesic medication, extracorporeal prosthetic (cane or brace), implanted prosthetic (joint replacement) or injection of lubricious media.
Braces are of several varieties. One variety limits range of motion, mostly to limit potentially harmful movement in patients following injury or surgery. Another variety of brace is an unloader brace—which is intended to provide relief mostly for those with arthritis. When an unloader brace is functioning in accordance with the design principles, eccentric forces are applied to avoid the most damaged portion of the joint. Compressive force on the cartilage deficient bone portion of the joint is reduced. This brace often accomplishes its goal by shifting the load medially or laterally away from the most damaged portion of the joint. Alternatively it is simply applied tightly enough as to cause an increase in the gap between bone surfaces—as by reverse barreling or the Poisson effect. There are many unloading knee brace products and patents, for example U.S. Pat. No. 5,277,698.
Other braces are also intended to be affixed to the person and bear all or part of the load of the affected joint; and in addition have a mechanism to lock the brace. For example U.S. Pat. No. 5,490,831 discloses a knee brace in which the articulating hinge can be locked at a fixed angle to assist in walking. The brace incorporates a heel strike mechanism as a trigger for the locking mechanism. Similarly, U.S. Pat. No. 6,635,024 discloses a brace that can be manually locked to allow the brace to support the weight of the patient while standing.
Foot Ulcers
Another big need for an accommodating brace is reduction of load borne by foot ulcers during normal walking activity. Load on foot ulcers inhibits healing and exacerbates the condition. If the ulcers are not healed, amputation can be necessary to preserve the life of the patient.
There are about 20 million diabetics in the US and about 200 million worldwide. 15% of diabetics develop foot ulcers during their lifetimes. Every year about 5% of diabetics develop foot ulcers. There are about 120,000 hospital amputations of lower extremities each year in the US, 60% of these are diabetic patients. It has been reported that it typically costs over $20,000 to treat a foot ulcer over the 2 years following the initial diagnosis. Clearly there are good reasons, financial and compassionate to reduce the severity of foot ulcers, and to promote healing. This can be accomplished by the use of a brace that reduces or eliminates the load on the foot during normal activities.
A frequent complication to foot ulcers is neuropathy that severely reduces patients' ability to sense foot pressure or pain. Without this feedback, patients will be unaware of continued damage due to unsafe loading of the affected area. Consequently, more passive treatment approaches are necessary to treat these patients.
Treatment of foot ulcers includes dressing and debridement, braces, orthotics, footwear and even total contact casting (in which the foot and lower leg are encased in a cast to inhibit weight bearing on the foot ulcer). It is crucial to reduce load bearing of foot ulcers, because load bearing retards or even reverses the healing process.
Foot Apparel
Another closely related technology is closure and tightening technologies for athletic footwear. In 1989 Reebok sold athletic shoes that used a manually operated integral air pump to tighten the fit of shoes. Competitors for the Reebok Pump included LA Gear Regulators and Nike Air Pressure. There are many patents that disclose inventions that use bladders and other systems to allow the user to manually improve fit, beyond the conventional lacing or Velcro strap systems, such as U.S. Pat. No. 4,662,087, U.S. Pat. No. 4,763,426, U.S. Pat. No. 5,113,599 and U.S. Pat. No. 4,995,173.
Another patented athletic shoe closure includes the Boa system, and the U.S. Pat. Nos. 5,934,599, 6,202,953, 6,289,558. These shoes use a manually operated reel to snug a cable that tightens the fit of the shoe.
Patent application 20090272007 Automatic Lacing System of Beers et. al. assigned to Nike, Inc. teaches a lacing system for footwear that uses a motor to drive an assembly that tightens laces or straps when activated. This is reputed to be the power laces system that gained notoriety when depicted in the film Back to the Future II.
Limitations of Present Technologies
The aforementioned treatment alternatives have limitations. The medication treatment options can reduce pain, infection and inflammation in many people—though often incompletely. Additionally, these can have deleterious systemic side effects. These unwanted effects can sometimes be severe—such as ulceration and hemorrhage (particularly gastro-intestinal).
Use of a cane to relieve the pain of an arthritic knee indeed has some history of success by diverting weight to the arm instead of the knee. The knee thus does not have to bear as much compression so the compressive and shear stresses experienced by the surfaces of the femur and tibia are diminished. Understandably, the lower stresses result in diminution of pain. Of course the use of a cane mandates an unnatural gait and occupies one hand—so a cane does have large limitations. Additionally, the off-loading by a cane is highly variable and unreliable, especially with patients who have neuropathy.
Implanted total or partial joint replacement can greatly relieve symptoms. Limitations of this solution include cost, pain and risk of surgery. Also, any failure of the replacement joint necessitates additional surgery and attending cost, pain and risk.
Injection of lubricious media (such as viscous hyaluronic acid) within a joint has experienced mixed results. There has been relief of arthritis symptoms—though generally temporary.
Often arthritis sufferers have asymmetric joint wear. A person who has excessive cartilage wear in the medial portion of the joint may benefit from an unloader brace that shifts the load laterally. This is generally accomplished by judicious application of the attachment straps that redistribute the weight of the patient through the less diseased portion of the joint. This implies that the healthier portion of the joint bears a larger than normal load. For an unloader brace to function properly, it must be tight—tight enough to force the wearer to stride in an unnatural gait that shifts the load. Thus limitations of the unloader brace are that it can not always achieve sufficient relief of symptoms and that if it is tight enough to do so, that it is often uncomfortable. Additionally, if there is slippage of the brace with respect to the joint the functionality can be compromised.
Braces of the sort disclosed in U.S. Pat. No. 5,490,831 would suffer from similar shortcomings. They must be tight to work at all—slippage frustrates the effectiveness of the braces. In addition they are large and cumbersome. Also, though relatively rigid, they do not reduce the load on the knee as an unloading brace does.
Prior art devices, even those that share load with the joint, are designed to (at most) limit how much the joint is compressed. They can bear part of the compressive load that would otherwise be fully borne by the joint. They do not apply counter force or impose motion in the opposite direction of the compression to spare the joint.
In the treatment of foot ulcers, dressings and debridement can promote healing, but this is futile if the patient continues to apply pressure to the ulcer by walking on it. Braces, orthotics and footwear can reduce the stress on the ulcers, but patients often do not comply with the directive to avoid walking without them. Patients do about 50% of their walking at home, but they only wear the footwear that protects the ulcers about 15% of the time at home. This is because the footwear can be uncomfortable and inconvenient. For this reason, total contact casting is often used, so that the patient cannot remove the footwear. Though this does improve compliance, a cast is heavy and uncomfortable, and it blocks access to the ulcer—compromising the care of the ulcer. Additionally, some suggest that because casting requires more intensive and fairly uncommon “fitting” skills, it is underutilized.
There is thus a need for footwear that is more convenient with better therapeutic potential than currently available options that reduces load on foot ulcers.
It is an objective of the invention to accommodate to user status. It is an objective of the invention to appropriately increase fixation force as needed when the wearer uses the affected joint or body part.
With respect to joint problems, it is an objective of the present invention to provide accommodating apparatus that reduces load on a joint or surface during use.
It is another objective of the invention to apply counter force (or to increase the distance between bearing surfaces of bones in an affected joint) when the brace wearer uses the affected joint. It is a further objective of the current invention to apply unloading force around the joint during load bearing and to substantially remove the unloading force during non-load bearing intervals.
It is a further objective to minimize the degree of slippage of the brace compared to current braces or to automatically reverse the slippage and so to maintain functionality during prolonged used.
Another objective is to continuously and automatically adjust the brace to physiological changes experienced by the patient (e.g. reduced edema) to maintain the targeted off-loading force throughout its prescribed use.
With respect to athletic footwear, the current tightening systems require manual user interface to achieve the optimal fit. There is thus a need for athletic footwear fit systems that require less activity from the wearer; i.e. the shoe should perform more of the work in tightening and or sensing.
Another objective of the current invention is to also apply force on the body to reduce edema, to improve venous drainage and/or to improve arterial perfusion and lymphatic circulation.